论文标题
强大的lyman- $α$和[CII]发射极的档案发现z = 7.677
The archival discovery of a strong Lyman-$α$ and [CII] emitter at z = 7.677
论文作者
论文摘要
我们报告了Lyman-$α$从$ z = 7.677 $中的lyman-$α$排放的档案发现，其电离碳[CII] 158 $μ$ m发射线在光谱上确认。 ly $α$线在空间上与剩下的紫外线恒星排放（$ m _ {\ rm uv} $〜-22，2倍，比$ m^\ star _ {\ rm uv} $亮2倍，并且它似乎是从扩展的[cii]排放的峰值上偏离了当前的〜1“ spatial 〜1” spatial〜我们的峰值。 sfr（uv）= $（22 \ pm1）\，m_ \ odot $ yr $^{ - 1} $，并设置sfr（ir）$ <15 \，m_ \ odot $ yr $^{ - 1} $的上限，从远达波长中，从全球范围内y002 y002 in y002 ins y002 ins sfr（corm corr）corr（uv+ir） - 在速度方面，$ΔV$（LY $α$）的峰值降低了$ 500 km s $^{ - 1} $，从[CII]设置的系统性红移中估计Z〜6-7的类似紫外线发射器，这可能表明我们目睹了两个团块的合并。 ew（ly $α$）= $ 24^{+5} _ { - 6} $Å。 $α$和[CII]发射区域。
We report the archival discovery of Lyman-$α$ emission from the bright ultraviolet galaxy Y002 at $z=7.677$, spectroscopically confirmed by its ionized carbon [CII] 158$μ$m emission line. The Ly$α$ line is spatially associated with the rest-frame UV stellar emission ($M_{\rm UV}$~-22, 2x brighter than $M^\star_{\rm UV}$) and it appears offset from the peak of the extended [CII] emission at the current ~1" spatial resolution. We derive an estimate of the unobscured SFR(UV)=$(22\pm1)\,M_\odot$ yr$^{-1}$ and set an upper limit of SFR(IR)$<15\,M_\odot$ yr$^{-1}$ from the far-infrared wavelength range, which globally place Y002 on the SFR(UV+IR)-L([CII]) correlation observed at lower redshifts. In terms of velocity, the peak of the Ly$α$ emission is redshifted by $Δv$(Ly$α$)~500 km s$^{-1}$ from the systemic redshift set by [CII] and a high-velocity tail extends to up to ~1000 km s$^{-1}$. The velocity offset is up to ~3.5x higher than the average estimate for similarly UV-bright emitters at z~6-7, which might suggest that we are witnessing the merging of two clumps. A combination of strong outflows and the possible presence of an extended ionized bubble surrounding Y002 would likely facilitate the escape of copious Ly$α$ light, as indicated by the large equivalent width EW(Ly$α$)=$24^{+5}_{-6}$ Å. Assuming that [CII] traces the neutral hydrogen, we estimate a HI gas fraction of $M({\rm HI})/M_\star\gtrsim8$ for Y002 as a system and speculate that patches of high HI column densities could contribute to explain the observed spatial offsets between Ly$α$ and [CII] emitting regions. The low dust content, implied by the non-detection of the far-infrared continuum emission at rest-frame ~160 $μ$m, would be sufficient to absorb any potential Ly$α$ photons produced within the [CII] clump as a result of large HI column densities.
